EP1440828A2 - Method for determining the temperature of a motor vehicle passenger compartment, device for carrying out the method and temperature sensor - Google Patents

Abstract

The involves determining air circulation in front of a measurement point for use as a weighted correction value, determining and storing the sensor reaction with the air at rest in an adaptive measurement, applying a signal to an additional heating element, which is read out at the sensor as a step response and determining the presence/absence of an air flow from the difference between the step response and adaptively determined reaction. The method is based on a solar radiation parameter determined at a sensor and/or a surface temperature at the measurement position at a further sensor. It involves determining air circulation in front of the measurement point, which is fed into the determined solar radiation as a weighted correction value, determining and storing the sensor reaction with the air at rest in an adaptive measurement, applying a signal to an additional heating element, which is read out at the sensor as a step response and determining the presence/absence of an air flow from the difference between the step response and the adaptively determined reaction. Independent claims are also included for the following: (a) an arrangement for implementing the inventive method (b) and a temperature sensor for determining the interior temperature especially of a motor vehicle passenger compartment.

Description

To automatically regulate the interior temperature in a vehicle, it is necessary the actual indoor temperature at a given time know. As a rule, a manipulated variable is then formed, which is the deviation of the reflects the actual interior temperature from the desired interior temperature. The manipulated variable is used to correct the difference. Such a process is described in DE 40 24 431 A1.

DE 198 29 143 C1 is a further method for changing the interior temperature of a vehicle disclosed. To compensate for a change the actual value of the interior temperature as a result of external influences, such as, for example low outside temperature, are an indoor temperature sensor as well an outside temperature sensor is provided. The interior temperature sensor is located itself in the control unit.

DE 197 28 803 C1 discloses an arrangement for temperature measurement and / or control with a housing which has a temperature sensor in its interior for measuring the room temperature given outside the housing, one or more heat sources being present in and / or on the housing , In addition, at least one auxiliary temperature sensor is provided within the housing at a point whose temperature is influenced more by the heat flow from the heat source than the temperature at the temperature sensor.
A disadvantage of the last-mentioned solution is the large deviation of the measured temperature signal from the actual interior temperature due to the large disturbing influences on the sensor, and the large inertia of the sensor, which experiences changes in the interior temperature only with a time delay and smoothed. In these cases, therefore, a great deal of effort is required to correct the temperature signal.

From DE 100 16 419 C2 a device for indirect detection of the in the Interior of a vehicle is known to be incident solar radiation. A used here Photosensor is attached to the housing so that it is not a direct one Sun exposure is exposed and therefore only reflected in the vehicle interior or transmitted radiation measures the solar radiation.

Measuring methods are currently being developed which determine the interior temperature directly by means of an NTC (resistor with negative temperature coefficient) measure the surface of the control panel without forced ventilation. The unreliability this measuring method results from the changing air flow on the control panel surface, which the measured values at the NTC even when taking self-heating into account and relativize the influence of the sun.

DE 100 49 979 C2 describes a device for determining the temperature in the interior known a vehicle in which a temperature sensor behind one the interior wall is arranged. A heat conduction element is used to measure the temperature of the air inside the vehicle near the wall. The heat conduction element is in contact with the temperature sensor Thermal contact and is on or close to the wall or through an opening in the Wall attached. This device eliminates interference from partial Solar radiation recorded on the sensor housing and corrected accordingly.

The invention has for its object a method and an arrangement and Specify temperature sensor with which a satisfactory determination of the Indoor temperature taking into account a changing heat transfer resistance possible on the control panel surface to the surrounding air flow is.

The problem is solved by the features of claim 1, the claim 3 or claim 4.

The invention is based on the knowledge that, for example, in the case of solar radiation a sensor measuring this radiation when the air is still in front of the Sensor is heated up more than with moving air. The same effect occurs when measuring the temperature of a control panel surface due to the self-heating of the electronics on. Here too, measurement results are falsified by air circulation.

In order to eliminate this falsification from the measurement result using simple means, It is suggested that the presence of moving or still air before Measuring location, i.e. to determine the intensity of the air movement as such. This information is weighted and is used as a correction variable in the manipulated variable Regulation one, with the aim of considering the interior temperature of a vehicle the changing heat transfer resistance of the control panel surface to capture the surrounding air flow.

In the practical implementation of the idea, the design of the components with respect to one another is important in order to determine the influence of the air in front of the measuring location. For example, a heating element is attached in direct temperature coupling to a sensor, which is preferably already determining the temperature of the control panel surface. The sensor is slightly heated by the heating element in short pulses and for this in relatively large time intervals. The influence of the air flow can be determined from the difference in the step response in comparison to a reaction determined adaptively on the sensor when the air is still and the disturbance variables _" control panel heating" and particularly _" sun" can be weighted. A correction signal resulting from the weighting is included in the determination of the manipulated variable and the regulation.

In a preferred embodiment, both components are integrated in a sensor housing which is attached as an Incar sensor to the surface of an air conditioning control panel. The temperature sensor determining the control panel surface and the heating element are applied to a film in the housing, through which the desired temperature coupling of both is achieved.
Furthermore, the sensor has a pulse damping path between the two components, which is formed together with the film and conductor tracks.

With the help of the Incar sensor constructed in this way, the changing heat transfer resistances of the control panel surface to the surrounding air flow can be determined directly.

In a further preferred embodiment, the Incar sensor additionally includes or alternatively, besides the heating element and the NTC, a solar or light sensitive one Sensor that is used to determine the solar radiation at the measurement location.

If the control panel's own heating is also to be taken into account, the measurement can preferably one in the control system, i.e. in the control unit electronics NTC can be used, whereby the integration of an additional NTC in the Incar sensor is possible.

The Incar or temperature sensor is preferably manufactured using film injection technology (film injected with plastic) or using MID technology (Molded Interconnect devices = injection molded circuit carrier, see http://www.vdivde-it.de/smt/raeuml baugruppen.html) ).

The proposed Incar sensor eliminates the need for a sensor fan are avoided, thereby avoiding known disadvantages such as pollution and noise become. Furthermore, there are new possibilities in the design and construction of the Control units.

The invention will be explained in more detail using an exemplary embodiment with a drawing become.

Fig. 1 a - c

den Aufbau eines Incar-Sensors in MID-Technik,

Fig. 2

einen Incar-Sensor in Folientechnik in Draufsicht,

Fig. 2a

den Sensor aus Fig. 2 im Schnitt A-A,

Fig. 2b

die Folie aus Fig. 2a in einer Draufsicht,

Fig. 3

ein Bedienteil mit Incar-Sensor in einer Draufsicht,

Fig. 4

ein Impulsdiagramm zur Darstellung des Einflusses der Luftzirkulation,

Fig. 5

eine Diagrammdarstellung der Sprünge der Lufttemperatur am Messort.

It shows

Fig. 1 a - c

the construction of an Incar sensor using MID technology,

Fig. 2

an Incar sensor in foil technology in top view,

Fig. 2a

2 in section AA,

Fig. 2b

2a in a top view,

Fig. 3

a control panel with Incar sensor in a top view,

Fig. 4

a pulse diagram to illustrate the influence of air circulation,

Fig. 5

a diagram of the jumps in air temperature at the measurement site.

1a to c are a compact sensor manufactured using MID technology 1 shown as an Incar sensor or temperature sensor in different views. 1 a shows it in a front view, FIG. 1 b in a side view and Fig. 1 c in a plan view, each in section.

The sensor 1 has a housing 2 which, for example, has a film 3 in the upper one, which acts as the substrate of the sensor 1. The housing is at the bottom 2 closed by a kind of potting compound 4. Can be seen on the slide 3 in the preferred embodiment, a heating element 5, for example a heating resistor Solar sensor 6, for example a photosensor, and an NTC element 7 from behind printed. The film 3 consists for example of PC or Macrolon. On the slide 3 are between the heating element 5 and the NTC 7 applied copper tracks or silver sheets to form a pulse damping section 8. In the housing 2 is located between the film 3 with the components 5, 6, 7 and the sealing compound 4 a thermal insulation material 9, which among other things. can also be air. As in Fig. 1 b shown in more detail, the electrical contact is made with a further not shown Signal processing unit via contact pins 10. Fig. 1 c shows the contact pins 10, which in turn via conductor tracks 11 each with the individual components 5-7 are in electrical contact.

2 shows a top view of an Incar sensor 20 manufactured using film technology. The sensor 20 shown here preferably has a housing 21 with the outer dimensions 17 x 8 x 3 mm.

FIG. 2a shows the sensor 20 in section AA from FIG. 2. Here, too, a heating element 22, a pulse damping path 23, an NTC element 24 are integrated in the common sensor housing 21 and a film 25 is printed from behind. The special flexibility of the film 25 enables the film 25 to be folded or kinked within the sensor housing 21. Chambers are formed by the folding.
Furthermore, in the preferred embodiment, the sensor 20 has a light-sensitive sensor 28, for example a photosensor. The film 25 is IR-transmissive at least in the area of the photosensor 28 located underneath. A film web 26 with a zero-force plug connector 27 serves as a contact to the evaluation unit (not shown in any more detail). The attachment of a further NTC 29 within the sensor housing 21 is also positive. This can be used to determine the heating of the operating part of the control unit. For this purpose, the housing 21 is open at this point. The housing 21 is preferably in several parts and can be clipped into one another via snap projections.

The sensor 20 is preferably manufactured as follows:

The heating element 22 is brought directly onto the film 25 using thick-film technology. The NTC 24 can then be glued or soldered onto the film 25 using conductive adhesive. The heat conduction or damping section 23 is also directly on the film 25 applied. As already mentioned, the film 25 can be made of polycarbonate or polyimide etc. exist, which preferably has IR-transparent areas. The foil 25 is then inserted into the sensor housing 21, preferably glued into it and injected. If the film material is not made of IR-transparent material exist, the film 25 can alternatively be covered with an IR-transparent lacquer become, completely or only partially, at least in the area of Photosensor 28.

3 shows a sketch of an operating part 30 in a vehicle interior of a motor vehicle (not shown in more detail). Also shown is an NTC 31 located in the control panel 30, which can be used to determine the control panel's own heating.
Due to the fact that the upper area of the compact temperature sensor 1, 20 points into the interior, the solar radiation 6 or the light-sensitive sensor 28 can be measured in a known manner with the aid of the solar sensor 6 or the light-sensitive sensor 28. The control panel surface temperature, which corresponds to the air temperature in the interior, can be determined via the NTC element 7 or 24 located in the temperature sensor 1, 20.

Both information do not yet take into account the air circulation (arrow) in front of the control unit 30. This determination is made with the help of the heating element 5, 22 and the NTC 7, 24 and based on the knowledge of the heat content of the mass of the film 3, 25 and the damping section 8 , 23, whose materials are known. In a first adaptive measurement, the reaction with still air L _{rest is} determined and stored on the NTC element 7, 24. Short pulses S are then _{normally applied} to the heating element 5, 22 at relatively large time intervals, which slightly heats the NTC 7, 24. One or no air flow is determined from the difference of the step response in comparison to the response when the air L _rest is adaptively determined at the NTC 7.
The damping of the pulse S _normal sent via the pulse damping path 8, 23 thus serves as information about the type of air movement.
In practice, it has been shown that the step response on the NTC element 7, 24 varies depending on the air movement, since the heat information from the heating resistor 5, 22 is damped by the moving air. The course of the curve when the air is at _rest L _rest thus differs significantly from the curve when the air L is _moving , namely by different pulse _widths and pulse heights, as shown in FIG. 3.

Knowing whether it is moving or still air then leads to a weighting of the solar radiation and thus the weighting of the measured interior temperature. If moving air L _{bew is} determined, the solar radiation into the passenger compartment is consequently higher than the measured one, and when the air L _{rest is at rest,} the measured value corresponds to the current value of the interior temperature. In continuation of the method and taking into account the determined self-heating of the measuring location / control panel 30, for example with the additional help of an NTC 31 of the control panel 30, a correct interior temperature is determined with the aid of the weighted variables.

The weighted air movement is therefore used as a correction variable in the disturbance variables sun and control panel self-heating and thus in the control. Both can too are included separately or weighted as individual quantities in the regulation.

Due to the inertia of unventilated temperature sensors, jumps in the air temperature in the passenger compartment can only be detected with a delay. As a result of different air flows on the sensor surface, there is a variable heat transfer resistance to the air in the passenger compartment. Temperature jumps in moving air are transmitted faster than in still air (Fig. 5).
A further advantageous approach results from the determined air movement in front of the control unit 30 (or the measurement location for the interior temperature in general). By recording a real time constant, a change in the temperature can be concluded at an early stage, which enables rapid intervention in the control. Based on the step response, an expected final value can also be determined. This also results in targeted intervention in the climate regulation.

reference numeral

1

Incar Sensor

2

casing

3

foil

4

sealing compound

5

Heating element, heating resistor

6

photosensitive sensor

7

NTC element

8th

Thermal conduction or damping section

9

Thermal insulation material

10

contact pins

11

conductor tracks

20

I ncar sensor

21

casing

22

heating element

23

Thermal conduction or damping section

24

NTC element

25

foil

26

Folienbahen

27

ZIF connector

28

light-sensitive sensor (photodiode, transistor)

29

NTC element

Claims (15)

Method for determining the interior temperature, in particular of a passenger compartment, on the basis of a quantity for the solar radiation determined on a sensor (6, 28) and / or a surface temperature at the measurement location (30) determined on a further sensor (7, 24), characterized in that an air circulation in front of the measuring location (30) is determined, which weighted as a variable heat transfer resistance is included as a correction quantity at least in the determined solar radiation, for which purpose in a first adaptive measurement at the sensor (7, 24) is determined, the reaction at the sensor (7, 24) with still air (L _ruh) and stored, an additional heating element (5, 22) is subjected to a signal (S _normal ), which is read out as a step response (L _rest , L _bew ) on the sensor (7, 24), whereby an existing or non-existent air flow is determined from the difference in the step response in comparison to the adaptively determined reaction. A method according to claim 1, characterized in that when there is air movement, the step response (L _bew ) at the sensor (7, 24) has a smaller pulse height and a smaller pulse width than the step response (L _rest ) when the air is still. Arrangement for performing the method according to one of claims 1 or 2, having a sensor (6, 28) for measuring the solar radiation and / or at least one sensor (7, 24) for determining a surface temperature at the measuring location (30) and a heating element (5, 22) in the immediate vicinity and with thermal coupling to this sensor (7, 24). Temperature sensor for determining the interior temperature, in particular one Passenger compartment, comprising at least one sensor (7, 24) for determining the Surface temperature of the measuring location (30) and a heating element (5, 22), which is thermally coupled to the sensor (7, 24). Temperature sensor according to claim 4, characterized in that the thermal coupling takes place via a damping path (8, 23). Temperature sensor according to claim 5, characterized in that the damping path (8, 23) is formed by a film (3, 25) and conductor tracks applied thereon. Temperature sensor according to one of claims 4 to 6, characterized in that the temperature sensor (1) is housed in a housing (2), In the upper area, the film (3) is arranged, which functions as the substrate of the temperature sensor (1) and on which at least the sensor (7, 24) for determining the surface temperature of the measuring location (30) and the heating element (5, 22) are back-injected are and the housing (2) is closed at the bottom by a sealing compound (4) through which contact pins (10) are guided. Temperature sensor according to claim 7, characterized in that the housing (2) at least above a further sensor (6) located on the film (3) for measuring the solar radiation consists of an IR-transparent material. Temperature sensor according to one of claims 4 to 6, characterized. that the temperature sensor (20) is accommodated in a housing (21), the film (25) is flexible and with the sensor (7, 24) mounted thereon for determining the surface temperature of the measurement location (30) and the heating element (5, 22) is integrated and folded inside the housing (21) and Foil webs (26) are guided out of the housing (21). Temperature sensor according to claim 9, characterized in that a further NTC (29) for determining a self-heating of the operating parts is mounted in the housing (21) on the film (25) and the housing (21) is open in this area. Temperature sensor according to claim 9 or 10, characterized in that the sensor (28) measuring the solar radiation is applied to the film (25) and the housing (21) in the region of the sensor (28) has an IR-transparent region. Temperature sensor according to claim 11, characterized in that when the sensor (28) is arranged below the film (25), the film (25) in this area consists of IR-transparent material. Temperature sensor according to one of claims 7 or 8 manufactured in MID technology. Temperature sensor according to one of claims 9 to 12 manufactured in foil injection technology. Temperature sensor according to one of claims 1 to 3, characterized in that the NTC (24) is used as the heating element.

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